The Turkey international provided the finish in the 86th minute as the Spanish side came from behind against the Portuguese champions.
The Portuguese champions found it difficult to get through their visitors’ defense for much of the evening, but Jackson Martinez did gave them a 16th-minute lead with an excellent header.
Chelsea was the last side to defeat Porto at Estadio Dragao in November 2009, and that run came to an end in the second half thanks to Diego Godin and Turan.
Atletico followed up their its league victory over Real Madrid since 1999 over the weekend and Diego Simeone unsurprisingly made few changes. Koke and the suspended Diego Costa came out of the starting 11, with Raul Garcia and Leo Baptistao taking their respective places.
The first 15 minutes saw Porto struggle to break Atletico down in open play, but all Paulo Fonseca’s side needed was a free kick, and in the 16th minute it got its breakthrough. Tiago fouled Josue on the left and the 23-year-old curled an inviting delivery into the area that Martinez knocked past Thibaut Courtois with a diving header, holding off Godin in the process.
Simeone’s team looked significantly more motivated at the beginning of the second period, and eight minutes in Luis Filipe narrowly missed the target with a shot from 30 yards.
After its encouraging start, Atletico equalized in the 58th minute as Godin atoned for his role in Martinez’s opener. The Uruguayan rose highest to nod Gabi’s free kick past Helton, who needlessly rushed out in an attempt to punch the initial delivery away.
A few seconds after replacing Lucho Gonzalez, Juan Fernando Quintero fired a free kick just past Courtois’ left-hand post as Fonseca looked to make his side more dynamic in attack.
Helton denied Garcia in the 76th minute, but he could not nothing to prevent Turan with just four minutes of normal time remaining.
A neat free kick routine saw Gabi pass through the Porto wall, and the Turkey international smashed his effort past Helton from close range, completing Atletico's first away win against Portuguese opposition in eight attempts.